In vitro evaluation of two microleakage detection tests

Two microleakage detection tests were evaluated to compare their capabilities for revealing the extent of leakage at the interface between amalgam restorations and tooth structure. Class V cavities were prepared in the buccal surfaces of extracted human canine and premolar teeth and were treated in one of the following ways: no liner or varnish, a copal varnish, or an adhesive resin liner. The cavities were restored with a high-copper single composition spherical amalgam alloy and the specimens thermally cycled. Following storage for 6 months, the teeth were exposed to separate solutions of 45Ca and an ultraviolet fluorescing dye. The teeth were hemisected longitudinally and leakage was evaluated by determining the degree of penetration of the two tracers at the occlusal and gingival margins. Statistical analysis revealed a significant difference between the two leakage techniques (P less than 0.05). The radioisotope test generally indicated a greater degree of leakage than did the ultraviolet dye test.